This is a proposal for the participation of St. Jude Children's Research Hospital (SJCRH) in the Pediatric Oncology Group (POG). The overall aim of this participation is to improve the treatment of children with cancer and to improve through collaborative studies our understanding of childhood cancer. The participation of SJCRH in the POG will include: 1) continued performance of independent studies which may develop into group wide studies, 2) collaborative laboratory studies involving biologic questions in childhood cancer, 3) contributing patients to selected group studies, and 4) cooperating in a major way in scientific and developmental activities in the group by committee participation and study design.